"They are not getting along at all. It's uglier than you think," a music industry source tells PEOPLE.

"They are each looking into solo projects. Nick and the Administration are working on another album. They are moving forward away from the Jonas Brothers. I think this is the beginning of the end."

Still, a source close to the band maintains that the guys are still talking, at least. "The idea that this is acrimonious is wrong," says the source. "The guys are all talking and haven't stopped talking ever."

The Jonas Brothers are canceling their tour – two days before it was set to begin, PEOPLE has learned. The reason?

"There is a deep rift within the band," their spokesman, Jesse Derris, tells PEOPLE exclusively. "There was a big a disagreement over their music direction."

Over the weekend, an argument between the trio – Nick, 21, Joe, 24, and Kevin, 25 – regarding the direction of the band and its music led to the decision to cancel their 19-date tour, which was to kick off Friday.

Whether on- or offstage, the Jonas Brothers have always presented a united front. But there's apparently one topic that spurs dissention in the ranks: Miley Cyrus.

In the latest issue of Out magazine, the siblings – Kevin, 25, Joe, 24, and Nick, 21 – tackle a variety of buzzy subjects, but when the conversation veers toward the controversial "Wrecking Ball" singer, the brothers aren't quite on the same page.